Magnetic drag for control of yarn tension



Nov. 15, 1955 s 2,724,065

MAGNETIC DRAG FOR CONTROL OF YARN TENSION Filed March 50, 1951 N V EN TOR.

ATTORNEY United States Patent O 1 2,724,065 MAGNETIC DRAG FOR CONTROL OF YARN TENSION Erwin J. Saxl, Harvard, Mass. Application March 30, 1951, Serial No. 213,323 2 Claims. (Cl. 316-93) The present invention relates to processing apparatus for filamentous materials, yarn tensioning and has. par ticular reference to a tension control device for the filamentous materials.

The principal object of the invention is to provide a hysteresis torque tensioning device for filamentous materials such as yarn and the like.

Another object of the invention is to provide a magnetic tensioning device which is adjustable to provide a desired constant tension.

An additional object of the invention is to provide a light weight magnetic tensioning device which has very little rotary inertia, and is therefore suitable for light, sensitive yarns.

A further object of the invention is to provide means for tensioning a filamentous material in process, whereby said material is held under tension even when processing is stopped, and the material will not become unduly slack.

With the above and other objects and advantageous features in view, the invention consists of a novel arrangement of parts more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claims appended thereto.

In the drawings,

Fig. 1 is a diagrammatic layout illustrating the application of the tension control device to yarn for a warper;

Fig. 2 is a side view of a preferred embodiment of the tension control device;

Fig. 3 is a side view of Fig. 2;

Fig. 4 is a section on the line 4-4 of Fig. 3; and

Fig. 5 is a perspective enlarged view of the magnet housing of Fig. 2.

It has been found desirable to provide a light weight magnetic tension control device, for obtaining a desired tension on warp yarns, winding machines and the like. The device is preferably adjustable, whereby each position for warp yarns, for example, may be set to provide a uniform tension, or may be set to provide different tensions for particular yarns when special finishing effects are required. To this end, I provide an adjustable magnetic field between a fixed magnet or magnets, and a pulley made of magnetic flux conducting material, such as iron, or magnetizable alloys of good magnetic permeability, the field intensity being varied by shifting the position of the magnet or magnets with respect to the pulley to adjust the air gap distance therebetween, the preferred shifting being axial and in small increments, as the field intensity varies essentially inversely as the square of the air gap distance.

Referring to the drawings, Fig. l is a schematic layout of a tension control for one yarn for a warper section beam. The yarn is drawn off one package 11 mounted on a warping frame cone creel, not shown, and passes through a guide 12 to the tension control device 13, and through a guide 14 to the section beam 15.

The tension control device 13, see Fig. 2, includes a fixedsupport 16, having a horizontal bore 17 in which I 2,724,065 Patented Nov. 15, 1955 a shoulder 29 against which a pulley 30 seats, the pulley having an inner metal disk 31 made of magnetizable material, a pulley portion 32 which preferably has an outer v groove 33 for receiving a yarn and a central passage 34 in which a roller bearing 35 of standard type seats against the disk 31, the passage 34 being closed to yarn fibres and the like by a washer 36 and a disk washer 37, the shaft end 28 being swaged to lock the pulley in place. The combination of a V groove and an inner roller hearing reduces slippage of the yarn in the groove. The bottom of the V groove may be covered with material or processed to reduce slippage of the yarn on the pulley.

When a yarn 10 is passed around the pulley 30, the shaft 18 is shifted in its support 16 to align the pulley with the guides 12 and 14; the magnet housing 20 is then shifted axially to provide the proper air gap between the magnet device 24 and the pulley disk 31, whereby a definite magnetic restraining force is exerted on the pulley as it turns due to pull on the yarn, to provide a constant tension on the yarn.

The pulley being light weight, there is little inertia, whereby the tension control device is sensitive in response to acceleration when the machine is started or stopped under tension. Since the number of parts is small, and the parts are readily assembled, the cost of manufacture is low.

- Although particularly applicable to warpers, the tension control device may be used for other yarns, wires, and threads, such as nylon and other plastic threads. The application of a constant tension to the manufacture of nylon threads is advantageous, as the threads can be given a controlled stretch, particularly while in a plastic state during manufacture, and the micelles thereby oriented to greatly increase breaking strength and elasticity of the synthetic yarn.

Although I have disclosed a specific constructional embodiment of the invention, it is obvious that changes in the size, shape and arrangement of the parts may be made to suit different tension control requirements, without departing from the spirit and the scope of the invention as defined in the appended claims.

I claim:

1. In a tension control device for warp yarns and other filamentous materials having a shaft support and a shaft with one end secured in said support, a yarn engageable pulley rotatably mounted at the other end of the shaft, theinner face of said pulley including magnetic flux conducting material, and a magnet carrier slidably mounted on said shaft between the support and the pulley for adjustable locking in set position adjacent the pulley, said carrier having a magnet device on its face contiguous the inner face of the pulley, whereby an air gap of predetermined spacing is provided between the magnetic flux conducting material of the pulley and the magnet device of the carrier and rotation of the pulley by engagement of the yarn therewith creates a magnetic drag.

2. In the combination of claim 1, said magnet device including two spaced bar magnets.

References Cited in the file of this patent UNITED STATES PATENTS 296,212 Park Apr. 1, 1884 847,597 Onsum Mar. 19, 1907 1,465,584 Cullough Aug. 21, 1923 2,293,748 Johnson Aug. 25, 1942 2,361,239 Ransom Oct. 24, 1944 2,431,908 Bartelson Dec. 2, 1947 2,519,882 Bullard et a1 Aug. 22, 1950 2,566,743 Okulitch Sept. 4, 1951 2,614,773 Ammerall Oct. 21, 1952 FOREIGN PATENTS 225,541 Switzerland May 1, 1943 

